Ignition apparatus



. Jan. 14, 1936.

J. L. ARTHUR 2,027,507

IGNITIONAP-PARATUS Filed Dec. 50, 1951 2 Sheets-Sheet 1 Jan. 14, 1936.

J. L.- ARTHUR 2,027,507

IGNITION APPARATUS Filed Dec. 30, 1931 2 Sheets-Sheet 2 Patented Jan. 14, 1936 IGNITION APPARATUS James L. Arthur, Anderson, Ind., assignor, by

mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation ware of Dela- Application December 30, 1931, Serial No. 583,969

4 Claims.

This invention relates to ignition apparatus for internal combustion engines and-particularly to engine suctioncontrol devices for controlling the timing of, the ignition.

It is an object of the present invention to provide for positively retarding the ignition while the engine is idling, while providing for the automatic advancing of the ignition when the throttle is opened to increase the speed' of the engine. 'In order to'accomplish this object. I provide means responsive to engine suction for retarding the spark while the engine is idling. I preferably connect the'suction'chamber of said means with a port in the intake manifold near the edge of the throttle, when closed, and on the engine side of the throttle. When the throttle is opened to cause the engine speed to increase substantially above idling speed, the suction at this port is insufficient to hold the spark timer in fully retarded position. Centrifugal means is provided for advancing'the spark as the engine speed increases.

Further objects andadvantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings:

- Fig. 1 is a diagram of the embodiment of the present invention, a portion of the apparatus being shown in section, the section being taken on the line |-l of Fig. 4.

Figs. 2 and 3 are charts showing the operation of the device. r

Fig. 4 is a fragmentary view partly in longitudinal section of an ignition timer equipped with a form of the present invention- Fig. 5 is a sectional view on the line- 5-5 of Fig. 4.

Fig. 6 is a sectional view on line 6-6 of Fig. 4.

Referring to Fig. 4, 26 designates anignition timer housing provided with a shank 2| having abearing portion 22 received by the well in an engine frame, a fragment of which is indicated at 23. The shank 2| provides a bearing for a shaft 24 driven by the engine in any suitable manner. Shaft 24 drives a weight plate 25 carrying studs 26 upon which are pivotally 'mounted weights 21 having arms 28 bearing against arms 29 attached to a sleeve 36. which provides a cam 3|. The arms 21 are urged toward the shaft 24 by springs 32 attached to studs 26 and to studs 33 carried by the arms 29. Cam 3| drives a distributor rotor 34 carrying a segment 'cated, by arrow ,46.

(Cl. 123-117) v 35 which moves past distributor posts 36 carriedv by a head 31. The segment 35 is connected to a spring conductor 38 bearing against a center button 39.

Referring to Fig. 1, the cam 3| operates upon a rubbing block 46 attached to a circuit breaker lever 4| carrying a contact 42 which cooperates with a grounded contact 43. The rubbing block 46 is urged toward the cam. by a leaf spring conductor 44 attached at one end to an insulating terminal 45 and at the otherend of the lever 4|. In the example given, the direction of rotation of the cam 3| is clockwise as indi- What has been described thus far is a conventional form of ignition timer to which the present invention can be applied as an attachment.

Screws 56a secure to the engine frame 23 shown in Fig. 1 a bracket to which nuts 5| and studs 52 attach a housing 53 having aflange 54 bent over the periphery of a housing 55 in order to secure at its edge a flexible diaphragm 56 which may be made of thin flexible metal or from a plurality of layers of varnished aeroplane linen or similar material. The housing 55 car ries" an internally threaded bushing 51. into which is secured a cap 58 to which is secured a connection 59 for a pipe 60 attached by connection 6| to a threaded opening 62 in a carburetor frame 53. The opening 62 communicates with a port 64 drilled through the carburetor frame, which port is at a point near the edge of the throttle valve 65 so that when the valve is in the closed or in idle position the port will be on the engine side of the valve 65 and so that when the valve is opened to any point beyond idling or low engine speeds the port will be on the carburetor side of the valve. The valve 65 is mounted on a shaft 66 which is operated in any suitable manner. The cap 58 provides a seat for a spring I0 which surrounds sleeve II and which is seated at its left hand end in a flange I2 provided by the sleeve II. The

' spring 16 therefore urges the sleeve ll against a washer 13 secured to the diaphragm 56 together with another Washer 14 by riveting over the shank 15 of a rod 16. The rod 16 passes through an opening surrounded .by a flange 11 provided by the housing 53 and through an opening 18 provided in the'bracket 50. The rod I6 is attached by a wire 19 to a stud through which the wire passes and to which the wire is secured by a screw 6| The stud 80 is swivelly connected with a clamping bracket 82 which is provided with clamping arms 83 which are forcedinto I vacuum in inches 'of mercury at the port. for

various engine speeds when the engine is operating to .produce sufficient torque to drive the vehicle along a level road. It will be noted that when the engine is idling, that is running between a speed corresponding to a vehicle speed from about 2 to 10 miles per hour the vacuum at the port 64 is relatively high and will be sufficient to overcome the spring III to advance the ignition and to move the diaphragm 56 toward the right to retard the ignition. As the speed of the engine is increased above 10 miles per hour in response to opening the throttle 55, the vacuum at the port 64 decreases very rapidly as indicated by curve b-c showing the vacuum at a speed between 10 and 30 miles per hour under road torque operating conditions. Curve c-d indicates that above 30 miles per hour the vacuum increases due to the increase in speed.

Referring to Fig. 3, the curve efahk represents the spark advance curve for an ignition timer controlled by combined centrifugal means and suction means. The centrifugal advance may be constructed so that it will start to advance the spark at 15 miles per hour from an initial advance of The centrifugal device advances the sparkin the manner represented by the line H. 1

The curve abcd shows the vacuum in inches of mercury at the port 64 as the throttle valve 65-is opened to cause the engine to operate to increase the speed of the vehicle when driving over a level road. It willv be noted that as the throttle 65 is opened to increase the speed from about 2 to miles per hour, the vacuum at the port 64 increases rapidly from about 10 inches of mercury indicated at A to about 17 indicated at point B. The spring II is overcome when the suction in inches of mercury ex ceeds 10 inches and the diaphragm 58 moves toward 'the right to retard the ignition from about +5 to about 10 as indicated by line e-f in Fig. 3. When the throttle is opened still wider to cause the engine to drive the vehicle about miles per hour, the vacuum falls of! rapidly at the port 64. Hence, the spring III, operates to advance the ignition as indicated by the line q-h. The flat portion ,f-'q of curve 'efah is due tothe fact that when the vacuum is at" port 64 above approximately H inches of mercury, the tube II will be drawn the full distance toward the right wherein the tube ll engages the cap 58 thereby preventing further retarding of the spark although the vacuum may increase substantially above 14 inches of mercury. At speeds above approximately 15 mile per hour as indicated by c-d in Fig. 2. the vacuum is insufficient to overcome the spring III 'which maintains the plate 82 in its maximum advance position. Therefore at speeds above 15 miles per hour the centrifugal device controls the advancing of the ignition as indicated by line h-k which represents the centrifugal ad-' vance under full load operating conditions. The dotted line e-h represents the fact that the advance is never less than 5 under full load operating conditions.

Thus there has been provided a control for ignition apparatus by which, when the vehicle speed is below a certain value, such .as when the engine is idling, the ignition timing is controlled by engine suction only to retard the spark. Above a certain engine speed the suction device is inoperative to retard the ignition and the control of ignition timing is effected solely by a centrifugal device. v

The suction device therefore does automatically which heretofore might have been done manually with respect to an ignition apparatus having combined manual control and centrifugal control. bustion engine will idle better when the spark is retarded, but automobile drivers seldom remember to retard the spark when idling. The result is, that due to slight unevenness of engine speed while idling with advanced spark, the engine may tend to stall. The possibility of stalling is increased by the advent of free wheeling in automobiles. The present inven-- tion therefore reduces the possibility of engine stalling since the spark is automatically retarded in response to engine idling conditions.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Ignition control apparatus for internal combustion engines having a fuel pipe through whichfla fuel charge is drawn to the engine cylinders comprising, in combination, acircuit breaker, a'cam for operating the breaker, and means for effecting a relative angular adjustment between the cam and circuit breaker in a direction to retard the spark timing while the engine is idling and in response to engine pro duced suction in the engine fuel pipe, said means including a suction chamber, a displacement member in said chamber, and a pipe connecting said chamber with the fuel pipe of the engine only at a point adjacent the edge of the engine throttle valve when closed and on the engine engine side of said valve} a displacement member in said chamber, and means for connecting the displacement member with the circuit breaker in order to vary the angular relation between the' circuit breaker and cam in a direction to retard the spark timing while the engine'is idling.

3. A spark timing control for internal. combustion engines, wherein a charge of fuel is drawn into the engine cylinders through the fuel pipe whereupon an angularly adjustable ignition timer becomes effective to cause the firing of the fuel charge, comprising in combination, the' combination with said ignition timer of means for effecting relative angular adjustment of the ignition timer in a direction to retard thespark timing while the engine is'idllng and in response to engine produced suction in the engine fuel pipe, said means including a succombustion tion chamber, a displacement member in said chamber, and a pipe connecting said chamber with the fuel pipe of the engine only at a point adjacent the'edge ofthe engine throttle valve when closed and on the engine side of said valve.

4. A spark timing control for internal combustion engines, wherein a fuel pipe supplies a fuel mixture drawn into the engine cylinders under reduced pressure to be'ignited, comprising in combination, a circuit breaker, a cam. for operating the breaker, and means for effecting a relative angular adjustment between the cam and circuit breaker in a direction to retard the spark timing while the engine is idling and in response to engine produced suction in the engine fuel pipe, said means including a suction chamber, a displacement member in said chamber, and a pipe connecting said chamber with the fuel pipe of the engine only at a point adjacent the edge of the engine throttle valve when v closed and, on the engine side of said valve.

JAB/ES L. ARTHUR. 

